1. Field of the Invention
The application relates to a liquid crystal display (LCD). More particularly, the application relates to an LCD that is characterized by favorable color saturation.
2. Description of Related Art
The LCD featuring advantages that include small and compact size, high definition, low power consumption, and no radiation has gradually replaced the conventional cathode ray tube (CRT) display and become the mainstream product in the market of the displays. However, in comparison with the CRT display, the LCD often requires a backlight unit for displaying images. The common backlight units in the LCDs include cold-cathode fluorescent lamp (CCFL) backlight units and light emitting diode (LED) backlight units.
Since a white LED is characterized by low heat generation, low power consumption, long service life, fast response speed, compactness, and is suitable for planar package, the evolution of the white LED is regarded as a “white illumination revolution”. Besides, the white LED has been gradually applied in backlight modules of portable displays and televisions due to its advantages of low power consumption, small size, and fast response speed.
In the commonly used white LED, a blue LED chip is often employed together with yttrium aluminum garnet (YAG), and the blue LED is easy to be packaged and has compact size. Recently, quantum dot remote phosphor has been increasingly applied to the LED. The quantum dot remote phosphor is a quasi-zero-dimensional nano material that is constituted by several or dozens of atoms. In the quantum dot remote phosphor, the movement of electrons within the three-dimensional space is confined, and thus the photoelectric properties of the quantum dot remote phosphor are rather different from the photoelectric properties of the bulk-type phosphor. For instance, quantum dot remote phosphor which has different size but is irradiated by the same exciting light source emits secondary light with different wavelengths. If the quantum dot remote phosphor with different size is mixed, and the well-mixed quantum dot remote phosphor is irradiated by the same exciting light, the secondary light with different wavelengths can be simultaneously generated.
Compared to the conventional organic phosphor, the quantum dot remote phosphor has favorable light emission efficiency. Hence, when the quantum dot remote phosphor is applied to the backlight unit of the LCD, it is expected that color saturation (NTSC %) of the LCD can be improved. Although the quantum dot remote phosphor can enhance color saturation of the LCD, the chromatic coordinate of the white dot often shifts. As a result, it is rather imperative to resolve the issue of the shifted chromatic coordinate of the white dot caused by the quantum dot remote phosphor.